1. Field of the Invention
The present invention relates generally to a method of and apparatus for decontaminating garments and soft goods, and more specifically, to the removal of radioactive particulate matter, chemical agents, toxins and/or biological agents as well as regularly encountered soiling materials from garments or other items of cloth, paper and rubber.
2. Brief Description of the Prior Art
A patent which purports to teach a method of decontaminating radioactive garments through the use of a dry cleaning solvent is U.S. Pat. No. 3,728,074. This system depends entirely on the filtration of nuclear particulates from the dry cleaning solvent as the dry cleaning solvent is circulated through the contaminated garments. Therefore, since the radioactive particulates are captured entirely by the filters, it is presumable necessary to replace those filters often. Also, this system operates under positive pressure and includes an expansion bag. Any leak in the system or rupture of the expansion bag will result in radioactive particulates being discharged to the atmosphere.
There is also in the prior art a method which seems to teach the cleaning of radioactive particulate material from industrial workers protective clothing through the use of a conventional laundry wash. This wash entails a standard 30 to 45 minute water washing using commercial detergent followed by a separate drying cycle of usually 60 minutes in a conventional hot air or other type textile clothes dryer. This system although effective in producing a clean looking garment, normally is so inefficient that from 20 to 35% of the clothing must be rewashed because insufficient radioactivity has been removed to permit reuse of the protective article. Moreover, this method generates quantities of radioactively contaminated wash water which must be diluted to safe concentrations before it is released or evaporated to a concentrate and then drummed and buried in an radiation waste burial facility. This makes the method very costly and time consuming.
There is little in the prior art dealing with the removal of chemicals or toxins such as pesticides and chemical warfare agents such as tabun, sarin, soman or mustard gas from articles of protective clothing. This is also the case with garments contaminated with biological contaminants. The military currently decontaminates protective articles contaminated with chemical agents through the use of high temperature steam. Although the article is decontaminated of chemical agents in this manner, it is also usually no longer suitable for reuse. Also, this method does nothing to deactivate or destroy the agent.
Accordingly, it is an object of the present invention to provide a method of and apparatus for decontaminating garments contaminated with radioactive particulates which dislodges such radioactive particulates by using a dry cleaning solvent.
Another object of the present invention is to provide a method and apparatus which captures and contains radioactive, chemical and biological contaminants removed from the garments.
A further object of the present invention is to provide a method of an apparatus for decontaminating radioactively contaminated garments in a single apparatus which also serves to dry the garments after completion of the wash cycle.
Another object of the present invention is to provide a method of and apparatus for decontaminating garments contaminated with pesticides and chemical agents such as those used in chemical warfare (e.g. HD, GD, GA, GB).
Further, it is an object of the present invention to provide a method of and apparatus for decontaminating garments contaminated with biological and toxin contaminants including anthrax, salmonella, botulinum, a mycotoxin commonly referred to as yellow rain and other viruses and bacteria which can be potentially used in warfare or terrorist activity.
A further object of the present invention is to provide a method and apparatus for decontaminating garments which limits the amount of contaminated waste generated.
Further, it is an object of the present invention to provide a method and apparatus which is self contained and relatively easy to transport so that it may be taken from site to site.
Another object of the present invention is to provide a method and apparatus which operates under negative pressure so that, should leaks develop, no contaminants will be discharged to the atmosphere.
A further object of the present invention is to provide a method of an apparatus for decontaminating garments having radioactive, chemical and biological contamination in a quick and efficient manner.
Further, it is an object of the present invention to provide a method and apparatus which can be operated on a continuous basis for relatively long periods.
Briefly stated, the foregoing and numerous other features, objects and advantages of the present invention will become readily apparent upon reading the detailed description, claims and drawings set forth hereinafter. These features, objects and advantages are accomplished by circulating a dry cleaning solvent through the articles to be decontaminated while the articles are being agitated so that particulate and chemical contaminants which may be radioactive, chemical and/or biological in nature may be dislodged or dissolved and removed from the garments.
After an initial wash cycle, the dry cleaning solvent containing suspended particulate and dissolved contaminants is dumped from the drum housing which provides agitation to the garments, into a distillation means. Chemical agents including pesticides and nerve, blister, and other incapacitating or killing agents such as sarin and mustard are also removed from the garments during this initial wash cycle because they are all highly soluble in the dry cleaning solvent, preferably trichlorotrifluoroethane referred to herein as the solvent.
Located in the distillation means is a neutralizing agent which serves to deactivate biological contaminants, chemically break down chemical contaminants to nontoxic or less toxic substances and to prevent the migration of chemical contaminants with the solvent while the distilling is being performed. During the second phase of the wash cycle, an initially contaminate free volume of dry cleaning solvent is continuously circulated through the agitating drum housing in which the contaminated garments are placed in a closed loop arrangement. The closed loop includes a filter for the removal of additional particulates dislodged from the garments and an adsorber which preferentially adsorbs chemical agents which have been dissolved in the dry cleaning solvent during this phase of the wash cycle.
Between the second phase of the wash cycle and the drying cycle, there is a rinse cycle. Residual solvent absorbed in the garments is extracted by pumping a quantity of clean solvent through the drum thereby rinsing the garments of the residual solvent.
During the drying phase, hot solvent vapor is circulated through the drum housing in closed loop fashion by a fan. A portion of the hot solvent vapor being circulated is run through a condenser and returned to the fan so that the vapor being circulated through the drum housing is not saturated thereby facilitating more rapid drying.
Solvent vapor generated in the distillation means is collected and condensed and returned to the secondary solvent tank in pure liquid phase.
In other words, the invention comprises the use of a drum housing similar to that used in conventional dry cleaning systems and the use of trichlorotrifluoroethane as the dry cleaning solvent. The solvent not only serves to dislodge contaminating particulate matter, but also solubilizes various pesticides and chemical agents used in chemical warfare. The contaminated solvent is then drained from the drum housing to a distillation means which serves a dual function. The first function of the distillation means is to distill pure solvent from the contaminated solvent dumped therein while the second function of the distillation means is to serve as a container for a neutralizing agent which destroys or deactivates both chemical and biological contaminants. The neutralizing agent is comprised of a mixture of calcuim hypochlorite or sodium hypochlorite and sodium hydroxide or potassium hydroxide. The concentration of calcium or sodium hypochlorite must be greater than 10% and the concentration of sodium hydroxide or potassium hydroxide must be greater than 1.0 Normal.
The biological contaminants coming in contact with this neutralizing agent are destroyed. The chemical contaminants coming in contact with this neutralizing agent are chemically broken down to either nontoxic or less toxic substances. The density of the neutralizing agent is less than the density of solvent and further the neutralizing agent is nonmiscible in solvent, because the neutralizing agent has a polar chemical configuration. Therefore, the neutralizing agent will float as a layer on top of any solvent dumped to the distillation means. Any chemical agent attempting to migrate from the distillation means with the solvent vapor must first pass through this layer of neutralizing agent. Upon contacting the neutralizing agent layer, the chemical contaminants are broken down to heavier components which settle out in the distillation means assuring that no contaminants migrate from the distillation means with the solvent vapor. The solvent vapor thus generated is then condensed and collected and placed in readiness for the next wash load.
Given the relatively small size required for the apparatus, making it not unreasonable to transport, and that washings may be performed consecutively, the invention is particularly adaptable to use by the military for decontaminating the protective garments of soldiers, and the like, at or near the place of battle.
Garments currently used by the military for protection against chemical warface contain a layer of activated carbon which serves to adsorb any chemical agents coming in contact with the garment thereby preventing the chemical agents from contacting the wearer of the garment. Since there is currently no effective or efficient method of stripping off chemical agents adsorbed by the activated carbon impregnated in the garment, once the garment becomes contaminated, it must be replaced. The invention disclosed herein allows the activated carbon contained in the garment to be cleansed of chemical agents and therefore be reused.
The entire wash and dry cycle of the present invention can be performed in less than 45 minutes. Thus, it is entirely feasible that mobile dry cleaning decontamination units can be used in battle field conditions to regenerate the protective quality of the garments worn under those type of conditions.